Method and means for diagnosing and treating allergy

ABSTRACT

Disclosed is a method for diagnosing allergy in a human or animal patient, wherein the level of species-specific lipocalin, especially lipocalin 2 in a human patient, is measured in a sample of said patient and wherein a lowered level of said lipocalin compared to the level of said lipocalin in the corresponding sample of a human or animal that has no allergy, is indicative of an allergy, as well as a kit for performing this method, and a kit for quality control of allergen molecules or extracts used for immunotherapy of allergy by determining its siderophore-iron ligand load and thus immunomodulatory potency.Further, lipocalin proteins for use in treatment or prevention of allergies are provided, preferably complexed with siderophore-iron ligands.

This application is a Continuation of copending application Ser. No.15/111,162, filed on Jul. 12, 2016, which is the National StageApplication under 35 U.S.C. § 371 of International Application No.PCT/EP2015/050126, filed on Jan. 7, 2015, which claims the benefit under35 U.S.C. § 119(a) to European Patent Application No. 14150965.3, filedon Jan. 13, 2014, all of which are hereby expressly incorporated byreference into the present application.

The present invention relates to the diagnosis and therapy of allergy.

20% of the industrialized population suffers from allergy, whichincludes symptoms like allergic rhinoconjunctivitis, dermatitis,bronchial asthma, oral allergy syndrome, angioedema, gastrointestinalsymptoms and anaphylactic shocks. However, the etiology of allergicsensitization remains poorly understood.

Allergy diagnosis is based on three main pillars, patient's history, invitro and in vivo Tests. In vitro tests include determination oftotal-IgE and allergen-specific IgE levels, whereas in vivo testsinclude skin prick, intracutaneous tests and oral provocation tests.Both in vivo as well as in vitro methods are necessary to accuratediagnose a patient with allergy. Hence, the development of in vitromethods that reduce the numbers of in vivo methods, would greatlyincrease patients' compliance and reduce side effects.

Only causative treatment against allergies is allergen immunotherapy bythe sublingual or subcutaneous route. During allergen immunotherapyincreasing doses of allergen are applied, resulting in the generation ofantibody-classes other than IgE. Successful immunotherapy is oftenaccompanied with decreased levels of allergen-specific IgE and increasedIgG4-levels.

The efficacy of allergen immunotherapy however varies dependent on theallergens used, in particular because the exact mechanisms ofdesensitization remain poorly understood or are under currentinvestigations. An important role in desensitization has been attributedto a counterregulation of the Th2-cytokine milieu, which leads to adecrease of allergen-specific IgE-levels. Furthermore, a reducedallergen-specific T cell response is observed, which optimally leads tothe generation of regulatory T-cells.

Hence, methods, which would result in an anti-allergic immune modulationor immune tolerance, clearly need to be developed (Roth-Walter et al.,Immunol. Lett. 2005; 100: 182-188; Roth-Walter et al., Allergy 2008; 63:882-890).

Why people or animals become allergic still remains elusive. Even thoughthe past decades have produced myriad information regarding the effectorphase of allergic diseases, very few information is available concerningthe sensitization phase.

Most studies on allergic disease, be it on respiratory, skin or ingestedantigens, is done in models where sensitization is achieved viaintraperitoneal application of suitable proteins, a route hardlyrepresentative of sensitization process in humans or animals.

However, despite the existence of several thousands of protein families,most allergens belong to a rather limited number of protein families. Sothe vast majority of aeroallergens deriving from animals belong to thelipocalin-family (Virtanen, Allergy 2001; 56 Suppl 67: 48-51) and plantallergens usually originate from the prolamin or cupin superfamilies andthe Bet v 1 family. All of these families are able to bind to lipids andfatty acids. They are either multimeric proteins or tend to formaggregates (Schoell et al, Journal of Immunology 2005; 175: 6645-6650).The majority of allergens can also be classified by their biologicalfunction having either 1) proteolytic, 2) enzyme inhibitory activity or3) transport function (Stewart et al., Clinical and Experimental Allergy1996; 26: 1020-1044).

In contrast to humans, the specific proteins to which animals patientsare allergic are less well defined, since tests are usually performedusing extracts containing a variety of proteins. However, dogs and othermammalians seem to have similar IgE-reactivity to same allergen epitopesas humans and can also be allergic to other animals like mites, cats,ticks and even to humans. Also here major allergens have been found tobe lipocalins (Jackson et al., Veterinary Dermatology 2005; 16: 32-38).

It is an object of the present invention to provide diagnostic andtherapeutic tools, especially for improving current diagnostic andtherapeutic techniques for human and animals suspected to have allergyor suffering from allergy, thereafter termed patients. A more specificobject is to provide biomarker monitoring for the course and success ofallergen immunotherapy.

Therefore, the present invention provides a method for diagnosingallergy in a human or animal patient, wherein the level ofspecies-specific lipocalin (in humans lipocalin 2) is measured in asample of said patient and wherein a lowered level of said lipocalincompared to the level of said lipocalin in the corresponding sample of ahuman or animal that has no allergy, is indicative of an allergy.

Moreover, the invention also provides the application of exogenous orendogenous (self) lipocalins such as LCN2 for humans and animals forimmunotherapy. More specifically, the level of lipocalins loaded withligands in their molecular pocket such as siderophores with or withoutiron, or retinoic acid, determined by the method of the presentinvention has predictive value for the success of prophylacticimmunotherapy (vaccine) or therapeutic immunotherapy of allergy, for themonitoring of allergen immunotherapy or the quality standardization ofallergen extracts and allergen molecules applied for immunotherapy inpatients.

The term “species-specific lipocalin” according to the present inventionis understood as being an autologous lipocalin protein being inprinciple present in and encoded and expressed by the genome of thespecies concerned, for example lipocalin 2 in humans or otherspecies-specific lipocalins as disclosed in table 1.

The present invention is based on the teaching that lipocalin 2(neutrophil gelatinase-associated lipocalin (NGAL=LCN2=24p3)) level isindicative of the presence of allergy and/or to determine sensitizationstate in allergic human and pet individuals. The present method istherefore suitable to diagnose allergy by measuring lipocalin 2 in asample of an individual whose status with respect to allergy has to bedetermined. According to the present invention, a lowered lipocalin 2level (compared to a “healthy” (i.e. proven non-allergic) individual) isindicative for the presence of allergy. With the present invention, adiagnostic tool is provided that allows i) a more accurate allergydiagnosis, ii) with a low sample volume only, iii) reducing the numbersof diagnostic skin prick tests, thereby increasing patients' compliance.For example, in the method according to the present invention less than10 μl serum is necessary for analysing lipocalin 2 levels, whereas forother tests (such as the ISAC ImmunoCAP method), at least 50 μl to 100μl blood are necessary.

Lipocalin has been suggested as a therapeutic agent against cancermetastasis in WO 2006/091035 A1. WO 2011/053832 A1 discloses the use ofurinary NGAL to diagnose sepsis in very low birth weight infants. Mölleret al. (AM. J. Cont. Derm. 9 (1998), 15-22) describes cytokines andacute phase reactants during flare-up of contact allergy to gold.Dittrich et al. (Clin. Exp. Allergy 40 (2010), 1689-1700) report thatLipocalin 2 protects against airway inflammation and hyperresponsivenessin a murine model of allergic airway disease. Ferreira et al. (Ad.Immunol. 84 (2004), 79-129) teach that recombinant allergens aresuperior to allergen extracts for desensitizing allergic patients.Kinnunen et al. (J. All. Clin. Immunol. 119 (2007), 965-972) show thataltered peptide ligands of lipocalin allergen Bos d2 can be beneficialfor peptide immunotherapy. WO 94/16068 A2 teaches that recombinantallergens from dog dander have advantageous properties. These documentsshow the clear prevalence of recombinant allergens as promisingtherapeutic lead substances in the field of allergy (and as areplacement for allergens derived from natural sources). Further—mostrecent—examples for this trend is Wallner et al. (Immunother. 5 (2013),1323-1338), Edlmayr et al. (Curr. Top. Microbiol. Immunol. 352 (2011),121-140) and Focke-Tejkl et al. (Curr. Opin. All. Clin. Immunol. 12(2012), 555-563).

Mori et al. (J. Clin. Invest. 115 (2005), 610-621) report that endocyticdelivery of lipocalin-siderophore-iron complex rescues the kidney fromischemia-reperfusion injury.

The present invention is based on the lipocalin function in the immunesystem. According to the present invention, a subset of the lipocalinsexerts significant immunomodulatory effects in vitro and in vivo.Interestingly, in humans most lipocalins are found in the q32-34 regionof human chromosome 9 and seem to exert anti-inflammatory functions(Lögdberg et al., Biochimica et biophysica acta 2000; 1482: 284-297).Indeed, murine lipocalin-2 (=24p3=NGAL) has been demonstrated to be animportant regulator in hematopoietic cell homeostasis. There are howeverconflicting data concerning its pro- or anti-apoptotic activities onlymphocytes, monocytes and erythrocytes (Liu et al., The Journal ofBiological Chemistry 2011; 286: 20606-20614). Lipocalin 2 (=NGAL) is aniron-trafficking protein involved in multiple processes such asapoptosis, innate immunity and renal development. The iron-free formtermed apo-lipocalin 2 seems to be anti-apoptotic, but also contraryresults have been reported with lipocalin 2 being pro-apoptotic in itsiron-free form and anti-apoptotic as holo-lipocalin 2. Despite thecontroversial data, it is clear that lipocalin 2 still has a profoundimpact on immune cells, as lipocalin 2-knockout mice have apoptoticdefects that seem to be restricted to relatively mature blood cellcompartments. Moreover, it was demonstrated that under immunesuppressiveconditions bone marrow-derived dendritic cells secrete high amounts oflipocalin-2. Lipocalin-2 is highly expressed in bone marrow and inbarrier tissues that are prone to exposure to microorganism likesalivary gland, colon and lung. In this respect, it is striking to notethat on the one side practically all respiratory allergens deriving fromanimals are lipocalins and that on the other side the lung is a site,where lipocalin-2 itself is highly expressed.

A further molecule that interacts with lipocalins is retinoic acid(Zsila et al, Biochem. Pharmacology 64 (2002) 1651-1660). Therebylipocalins can acquire immunomodulatory function on CD4+ T-cells (Austinet al, European Journal of Clinical Nutrition (2006) 60, 1266-1276; Hallet al, (2011) Immunity 34, 435-447; Lu et al, PLOS one (2010) 5; 12:e15150; Pino-Lagos et al, J. Exp. Med. (2011) 208; 9: 1767-1775).

The present invention also provides a method for the quantitative andqualitative determination of the iron-load of endogenous lipocalin orexogenous lipocalin allergens that is suitable for quality determinationof a lipocalin, an allergen extract or allergen molecule determined forprophylactic or therapeutic immunotherapy of allergy.

“Allergy” according to the present invention is preferably understood asIgE mediated type I allergy and preferably excludes immunoglobulinindependent T cell reactive type IV allergies (e.g. contact allergies).Contact allergies (Th1 and cytotoxic T cells) are mechanisticallycompletely distinct and remote from IgE mediated (Th2) allergies (whichare in the center of the present invention).

According to the present invention the level of lipocalin 2 or lipocalin2 mRNA is quantitatively determined by immunoassays such asEnzyme-linked Immunosorbent Assay (ELISA) or polymerase chain reaction(PCR) in any biological sample that can be taken from an individualsuspected of having allergy.

Preferred samples are those that can easily be provided from thepatients and that allow a specific testing of lipocalin 2 protein ormRNA. Preferably, the sample is a body fluid, selected from blood,serum, plasma, urine, tear fluid, lymph, mucus, or saliva, or easilyaccessible samples, such as hair and dander wherein lipocalin 2 is alsopresent. In these body samples, the lowering of lipocalin 2 in allergypatients or changes of lipocalin 2 during an allergy immunotherapy iseasily detectable without major efforts or problems for the patient.Specifically preferred, the body fluid is blood, serum or plasma and thepatient is a human patient. The patient may also be a veterinarianpatient, preferably dog, cat, or horse. Blood or blood derived samplesof human or veterinarian patients are easily available and providablealso for routine testing.

In a typical immunoassay, in parallel to the patient sample testing“standard” Lipocalin-2 is applied in a known concentration, (e.g. 10-50ng per test), or applied serially diluted (e.g. 10, 20, 50, 100, 200,500 ng or 1 μg per test) in duplicates or triplicates, to generate astandard calibration curve. Then the measurement results of the patientsample are compared to the standard Lipocalin-2 in order to determinethe relative amounts of Lipocalin 2 in the biological sample. The sampleitself may be applied directly onto the solid phase or applied to aprecoated “catching antibody” to Lipocalin-2. Bound Lipocalin-2 is thendetected by a (second) anti-Lipocalin-2 antibody which is directlylabeled by an enzyme (to be developed by addition of a substrate) orfluorophor. The resulting emission or absorbance is read in anelectronic device suitable for the method, e.g. an ELISA reader atabsorbance/emission optimal for the detection reagent. The signalintensity is directly proportional to the measured Lipocalin levels. Areduced Lipocalin-2 level would be indicative for allergy.

Lowering of lipocalin 2 levels in allergy patients compared tonon-allergy individuals is significant and therefore suitable forroutine testing of allergy patients, even for large scale testing orroutine diagnostics.

For example, the level of lipocalin 2 is lowered by at least 5% (withrespect to the ng lipocalin 2/ml body fluid), preferably by at least10%, especially at least 15%, compared to the level of lipocalin 2 inthe corresponding sample source of a human or animal that has no allergy(defining the 100% level).

According to a preferred embodiment, the level of lipocalin 2 accordingto present invention is determined by immunological techniques, such asELISA, ELISPOT, immunoblot, other solid phase assays, using e.g.radioactivity, fluorescence, chemiluminescence, etc.; alternatively,also the level of mRNA in the sample can be measured e.g. by (real time)PCR; specifically as only minimal amounts of material are neededaccording to the present invention.

According to another aspect, the present invention also provides a kitfor performing a method according to the present invention, comprising

-   -   means for detecting the level of lipocalin 2, especially a        molecule binding to lipocalin 2, and    -   means for comparing the level of lipocalin 2 to be detected with        the level of lipocalin 2 in a human or animal that has no        allergy.

The kit may be packaged in a sterile sale unit for diagnostic testing.The sale unit may be a single test sale unit or a multiple test saleunit (e.g. a sale unit with 5, 10 or 20 single tests in one sale unit).Preferably, all necessary components and information (product leaflets,instructions for use, etc.) are also provided in the sale unit. The testitself has not to be done in sterile condition and hence is ready touse.

In a preferred embodiment of the kit according to the present invention,the means for detecting the level of lipocalin 2 is a species-specificanti-lipocalin antibody or a lipocalin binding antibody fragment,especially an anti-human lipocalin 2 antibody or a human lipocalin2-binding antibody fragment. If various animal samples are determined,the corresponding antibodies against the homologous (species-specific)lipocalin 2 polypeptides are preferably used, e.g. anti-canine lipocalin2, anti-equine lipocalin 2 and anti-feline lipocalin 2 antibodies.

Examples of antibody fragments of the invention include (A) a “halfantibody” molecule, i.e. a single heavy:light chain pair, and (B) anantibody fragment, such as the univalent fragments Fab and the divalentfragment F(ab′)₂, and a single or double chain variable fragment, Fv.Antibody fragments according to the invention are preferably Fabfragments or antigen-binding regions such as sFv. Many kind ofantibodies and antibody fragments are known in the art. Antibodiesaccording to the invention include human antibodies, humanizedantibodies, chimeric antibodies, mammalian antibodies like murineantibodies, rat antibodies, camel antibodies; shark antibodies, andother antibodies of various animal sources known in the art.

Humanized antibodies are chimeric antibodies comprising non-human andhuman regions, and have reduced immunoreactivity when usedtherapeutically in humans. Typically, the variable domains or are ofnon-human origin and the constant domains are of human origin. Humanizedantibodies can also be produced by inserting non-humancomplementarity-determining-regions (CDRs) into the framework of a humanantibody. An antigen binding site in an antibody is made up of CDRs inthe light chain and CDRs in the heavy chain. Humanized antibodies can beproduced using recombinant DNA technology well-known in the art.Briefly, oligonucleotides encoding CDRs with desired antigen-recognitionproperties are used to replace the CDR regions in a human antibody gene.In certain instances, a mouse monoclonal antibody will have the desiredantigen-recognition characteristics. These CDR-encoding regions aresequenced and oligonucleotides encoding these regions are inserted intothe human antibody gene. Such techniques for humanization of antibodiesand cloning antibody (immunoglobulin) genes are well known in the art.

A fragment according to the present invention can be an Fv fragment. AnFv fragment of an antibody is made up of the variable region of theheavy chain (Vh) of an antibody and the variable region of the lightchain of an antibody (Vl). Proteolytic cleavage of an antibody canproduce double chain Fv fragments in which the Vh and V1 regions remainnon-covalently associated and retain antigen binding capacity.

Double chain Fv fragments also can be produced by recombinant expressionmethods well known in the art. Briefly, the amino acid sequence of thevariable regions of the heavy and light chains of antibodies known inthe art can be obtained by direct amino acid sequencing using methodswell known to those in the art. From this amino acid sequence, syntheticgenes can be designed which code for these variable regions and they canboth be inserted into an expression vector. Alternatively, nucleotidesequences known in the art that encode antibodies can be employed. Twopolypeptides can be expressed simultaneously from a mammalian orbacterial host, resulting in formation of an active Fv fragment.

An antibody fragment of the present invention also can be a single-chainmolecule or so-called “single chain antigen binding polypeptide,” aphrase used in this description to denote a linear polypeptide thatbinds antigen with specificity and that comprises variable orhypervariable regions from the heavy and light chain chains of anantibody. Single chain antigen binding polypeptides that retain anantigen-binding capacity that is characteristic of the present inventioncan be produced by conventional methodology. The Vh and Vl regions ofthe Fv fragment can be covalently joined and stabilized by the insertionof a disulfide bond. Alternatively, the Vh and Vl regions can be joinedby the insertion of a peptide linker. A gene encoding the Vh, Vl andpeptide linker sequences can be constructed and expressed using arecombinant expression vector.

Amino acid sequences comprising hypervariable regions from the Vh and Vlantibody chains can also be constructed using disulfide bonds or peptidelinkers.

Besides monoclonal antibodies or other (recombinantly) producedantibodies, also polyclonal antibodies specific for lipocalin 2 may beapplied in the present invention.

The kit according to the present invention may further comprise a marker(e.g. biotin, digoxygenin), which can be preferably detected bycolourigenic, fluorescent, luminescent, magnetic or radioactive means,especially a marker that is covalently linked to the means for detectingthe level of lipocalin 2 or a marker that is covalently linked to themolecule binding to lipocalin 2.

For example, the lipocalin 2-specific antibody or antibody fragment mayfurther include a radionuclide, enzyme, substrate, cofactor, fluorescentmarker, chemiluminescent marker, peptide tag, or a magnetic particle.The marker may be detectable by techniques well known in the art, forexample by colorimetry, fluorescence, scintigraphy, PET scan, NMR orX-rays. A preferred marker is biotin. The marker may also be present ona further detection molecule for the lipocalin 2 binding molecule, suchas a secondary antibody (or antibody fragment) binding to the (first)species-specific lipocalin 2-specific antibody or antibody fragment.

Alternatively, for the detection of the iron load of endogenous orexogenous lipocalin allergens, the autofluorescence of the molecule,respectively the quenching of this signal by addition of ligands, can bedetermined in relation to unloaded lipocalin.

Preferably, the kit according to the present invention further comprisesone or more standards for lipocalin 2.

Another preferred embodiment of the kit of the present invention is theuse of siderophores/ligand preparation with a defined amount ofligand/siderophore, where the ligand itself can be detected directly orindirectly e.g. by fluorescent, colorogenic chemiluminescent orradiological means.

According to this aspect, the present invention provides a method fordetermining the quantity of unloaded lipocalin 2. This quantity can bedetermined directly or indirectly. In the direct method the additione.g. of an unlabeled siderophore results in quenching of theautofluorescence of lipocalin proteins. If in the indirect method achromogenic, fluorogenic, chemilumenscenic siderophores is added it maycompete with the bound siderophores or extract ligands from siderophoresre-establishing the intrinsic autofluorescence of lipocalin proteins.The delta in signal intensity is then indirectly correlated to theamount of ligand loaded in the siderophore.

In these ligand-binding assays according to the present invention,siderophores loaded with iron or other ligands such as retinoic acid canbe specifically used for testing lipocalin allergens. Quenching of theautofluorescence of lipocalin allergens can be determinedspectrophotometrically. In the direct assays, the signal upon incubationwith the test siderophore or retinoic acid is inversely related to thenatural loading of the lipocalin allergen; in the competitive assay, thesignal upon incubation with the test siderophore or retinoic acid isdirectly related to the already bound ligand in the lipocalin allergen.For example, measurement of autofluorescence for the detection of theligand-load of lipocalin allergens can be performed in relation tounloaded lipocalin. Hence the method of this invention allowsclassification of lipocalin allergens as holo- or apo-forms.

Accordingly, the present invention also relates to a method fordetermining the quantity of unloaded lipocalin 2 in a lipocalin 2containing preparation wherein

(a) either a predetermined amount of test siderophore is added to thepreparation or(b) the preparation is competitively tested with iron-ligands not ableto bind to the lipocalin cavity, preferably desferral, that extractsligands from the lipocalin-pocket resulting in the reestablishment ofthe intrinsic fluorescence of the proteins; or(c) fluorescent, chromogenic, radiolabelled siderophore-iron-complexesare used directly or competitively for binding to the lipocalin cavityand wherein the quantity of unloaded lipocalin 2 is determined by(a) quenching of the autofluorescence of lipocalin proteins(b) autofluorescence of lipocalin proteins, or(c) measurement of bound siderophore.

Therefore, the present invention also relates to a method fordetermining the quantity of unloaded lipocalin allergen or lipocalin 2in a preparation wherein

(a) either a predetermined amount of siderophore, like 2,3,dihydroxybenzoic acid, is added to the preparation or(b) the preparation is competitively tested with iron-ligands not ableto bind to the lipocalin cavity, like desferral, that extracts ligandsfrom the lipocalin-pocket resulting in the reestablishment of theintrinsic fluorescence of the proteins at excitation/emission of 280/340nm.

According to another aspect, the present invention is drawn to lipocalinproteins for use in treatment or prevention of allergies, wherein thelipocalin is administered in the holo-form. The “holo-form” of lipocalinis defined as the combination of the lipocalin protein and a siderophoreloaded with a metal ion, especially an Fe³⁺ ion. According to theteachings of the present invention only the holo-form turned out to besuccessfully applicable in efficient treatment or prevention ofallergies. Only the holo-form showed efficient immunosuppressiveproperties, in contrast to the apo-form (without siderophore/Fe³⁺.Accordingly, only recombinant lipocalin allergens that have beensupplied with a sufficient amount of siderophores and Fe ions aresuitable according to the present invention. When naturally (i.e.non-recombinant; from natural sources) harvested single allergens areused in the method according to the present invention, care must betaken that siderophore and metal ions are either conserved in thepreparation or supplemented to the final product to be administered to apatient, because usual purification methods leading to single allergensalso eliminate siderophore and metal ion from the lipocalin allergen sothat only the apo-allergen is obtained.

The present invention therefore provides a therapeutic method oftreating, reducing, or ameliorating clinical manifestations of allergicdisease by administering to the allergy patient lipocalin 2 or otherlipocalin allergens in an amount effective to treat, reduce orameliorate allergic disease. According to the present invention it ismandatory that lipocalin 2 or other lipocalin allergen is administeredin the holo-form (as holo-lipocalin 2 or holo-lipocalin allergen).Therefore, the lipocalin 2 or other lipocalin allergen is presenttogether with a siderophore combined with a metal ion so that it can beco-administered with the lipocalin allergen. Up to now, when allergenimmunotherapy was performed with single allergen molecules, this wasdone with iron-free lipocalins, as the siderophores are lost duringproduction and purification. However, the apo-form has the undesirableintrinsic property to cause a Th2-shift by promoting CD4+ immune cells.It is also necessary that the holo-lipocalin 2 or other holo-lipocalinallergens are administered in purified form, i.e. as single allergenmolecules (or mixtures of recombinant or purified single allergenmolecules) and, however, less preferred, in the form of allergenextracts. The present invention therefore relies on immunotherapyagainst allergy, where lipocalin-allergens are administered incombination with iron-siderophores (=holo-lipocalin), thereby blockingthe Th2-skewing properties of lipocalin allergens and allowing the moreefficient generation of immune tolerance.

Most of the important mammal-derived respiratory allergens, as well asthe major milk allergen and a few insect allergens, belong to thelipocalin protein family as depicted in Table 1. Lipocalins wereinitially defined as powerful bacteriostatic agent active againstvarious Gram-negative microorganisms through impeding ironsequestration. They are involved in a variety of biological processeslike immune regulation, pheromone transport, prostaglandin synthesis andlipid transport. Lipocalin 2 has also been identified as a stressprotein that is released under various inflammatory conditions andcancer. Lipocalins vary greatly on the sequence level with unusually lowlevels of overall sequence conservation and pairwise comparison oftenfalling below 20%. Nevertheless, the lipocalin crystal structures arevery well conserved (Flower et al., Protein Science 1993; 2: 753-761).The lipocalin fold consists of an antiparallel 13 barrel structure madeof eight β sheets arranged in an antiparallel orientation resulting in acup-shaped cavity (the “calyx”) that binds, transports, and deliverssmall ligands (Flower et al., Biochimica et Biophysica Acta 2000; 1482:9-24). Lipocalins are usually secreted and can be found in the dander,urine, fur and saliva of animals and humans.

Lipocalin allergens induce T helper type 2 (Th2) deviation, when devoidof iron, but the reasons for this are enigmatic. Mammalian lipocalinsare thought to be on the borderline of self and non-self and hence to beable to amount a Th2-response under so far elusive circumstances(Virtanen et al., Clinical and Experimental Allergy 42 (2011), 494-504).It was recently discovered lipocalin allergens can mimic human lipocalin2 and increase survival in the apo-form, thereby being anti-apoptotic toCD4+ cells, whereas the holo-form severely impaired the expression ofCD4+ cells on peripheral blood mononuclear cells (see also: FIG. 3).Moreover, significant structural homologies with other major inhalativeallergens like Bet v 1 and Alt a 1 with the lipocalin-family wereidentified, providing the lipocalin-structure as a generalcharacteristics for most inhalative allergens (see also: FIG. 1).“Lipocalin proteins” according to the present invention are (human)lipocalin 2 and naturally occurring lipocalin-like proteins havingsequential topology of eight antiparallel beta-strands and forming acavity capable of binding siderophore-iron complex. With the presentinvention, the similar lipocalin structure of major allergens has beenproven, specifically the allergens explicitly referred to hereinafter.

TABLE 1 Lipocalins. The sequential identity of lipocalins varies but thethree-dimensional structure is conserved. They are present in bodyfluids and secretions and other samples of human and animal individuals.Lipocalins as allergens Bug Tria p 1 cat Fel d 4 Cockroach Bla g 4 cowBos d 2, Beta-lactoglobulin Bos d 5 dog Can f 1 and Can f 2 guinea pigCav p 1, Cav p 2, Cav p 3 horse Equ c 1, Equ c 2.0101 and Equ c 2.0102mite Der p 2, Aca s 13, Bt6, Lep d 13 mouse Mus m 1 rat Rat n 1 rabbitOry c 1 tick Arg r 1

With the present invention, lipocalin proteins are used to treatallergy; such “allergy treatment” also includes a reduction andamelioration of allergy symptoms.

According to the present invention, the lipocalin proteins areadministered mandatorily in combination with metal-ions, preferably Fe,Zn, Cu, Se or Mn ions, especially iron Fe³⁺.

In a preferred embodiment, the lipocalin proteins are administered incombination with siderophores, especially siderophores that arecomplexed with iron.

Lipocalin 2 or other lipocalin proteins as defined herein, especiallyDer p 2, Bet v 1 and Alt a 1 and all mammalian lipocalin allergens,cannot bind iron directly, but via siderophores. Siderophores areFe(III)-specific chelating agents in an organisms like catechols and arealso produced in the human body (e.g. adrenalin), but also by bacteriato invade the host, which enable them not only to bind to free availableFe(III) but also extract it from iron-binding proteins of the host.Siderophores (Greek: “iron carrier”) are small, high-affinity ironchelating compounds and are amongst the strongest soluble Fe³⁺ bindingagents known. Siderophores can be secreted by microorganisms such asbacteria, as well as fungi and grasses. Siderophores usually form astable, hexadentate, octahedral complex preferentially with Fe³⁺compared to other naturally occurring abundant metal ions, although ifthere are less than six donor atoms water can also coordinate. The mosteffective siderophores are those that have three bidentate ligands permolecule, forming a hexadentate complex and causing a smaller entropicchange than that caused by chelating a single ferric ion with separateligands. A comprehensive list of siderophores is presented in Hider etal., Nat. Prod. Rep. 27 (2010), 637-657. Fe³⁺ is a hard Lewis acid,preferring hard Lewis bases such as anionic or neutral oxygen tocoordinate with. Microbes usually release the iron from the siderophoreby reduction to Fe²⁺ which has little affinity to these ligands.

Siderophores are usually classified by the ligands used to chelate theferric iron. The major groups of siderophores include the catecholates(phenolates), hydroxamates and carboxylates (e.g. citric acid orderivatives of citric acid). The wide variety of siderophores may be dueto evolutionary pressures placed on microbes to produce structurallydifferent siderophores which cannot be transported by other microbes'specific active transport systems, or in the case of pathogensdeactivated by the host organism.

Lipocalin 2 exerts its bacteriostatic effect by binding to bacterialsiderophores as this lipocalin is released from the liver and spleen inresponse to an acute bacterial infection. There are several bacterialsiderophores however that cannot be trapped in the lipocalin 2-calyxlike desferal and pyoverdine and as a consequence allow bacteria toestablish infections in the lung. Desferal is used to treat acute ironpoisoning, especially in small children. This agent is also frequentlyused to treat hemochromatosis, a disease of iron accumulation that canbe either genetic or acquired. Apart from iron toxicity, deferoxaminecan be used to treat aluminium toxicity (an excess of aluminium in thebody) in select patients.

Lipocalin proteins are co-administered according to the presentinvention in combination with siderophores as a complex. “Complex” isunderstood herein in the usual manner, as non-covalent binding(H-bridges, van der Waals forces and electrostatic interactions) (seee.g. Gomez Casado et al., J. Mol. Graph. Mod. 45 (2013), 111-121).

Preferably, the lipocalin proteins are administered together with ametal-ion, preferably iron complexed with siderophores, in a molar ratioof 0.5 to 3 to 3 to 0.5, preferably in a molar ratio of 1 to 3 to 3 to1, especially in a molar ratio of 2.0 to 3 to 3 to 2.

According to a preferred embodiment of the present invention, lipocalinproteins are administered with zinc-, copper-, selen-, or mangan-ions.

It is preferred to administer lipocalin proteins with siderophoresselected from catechols, catechol-derivatives (compounds containing abenzene ring with two hydroxyl groups in ortho substitution).Preferably, the catechol (1,2-benzenediol) has further side chains,especially on positions 3, 4, 5 and/or 6, especially on positions 2, 4and 5. Also siderophores like α-hydroxycarboxylate,hydroxyphenyloxazolone, hydroxamate, α-aminocarboxylate,hydroxypyridinone, α-hydroxyimidazole and derivatives thereof can beadministered with the lipocalin proteins.

Preferred lipocalin proteins to be used for the treatment according tothe present invention are selected from human lipocalin 2, Amb a 1, Alng 1, Aca s 13, Act c 8, Act d 8, Act d 11, Alt a 1, Asp f 1, Asp f 3,Asp f 6, Art v 1, Api g 1, Api m1, Act d 2, Act d 8, Ara h 8, Arg r 1,Ber e 1, Bet v 1, Bet ch 1, Bet co 1, Bet le 1, Bet n 1, Bet p 1, Blot5, Bla g 1, Bla g 4, Bos d 2, Bos d 5, Bub b BLG, Can f 1, Canf 2, Canf 6, Cap h BLG, Car b 1, Cas s 1, Cav p 1, Cav p 2, Cav p 3, Cla h 8,Cyn d 1, Cyn d 2, Cyn d 15, Cor a 1, Cor he 1, Che a 1, Cup a 1, Dac g1, Dac g 2, Dac g 3, Dau c 1, Der p 2, Der f 2, Der f 13, Der p 13, Ecquc 1, Ecqu c 2, Fag s 1, Fra a 1, Fel d 4, Fel d 7, Gly m 4, Hol l 1, Homs TL, Hev b 8, Jug r 2, Lep d 13, Lol p 1, Lol p 2, Lol p3, Lyc e 4, Mald 1, Mer a 1, Mus m 1, Ole e 1, Ory c 1, Ory s 1, Ost c 1, Ovi a BLG,Pas n 1, Pha a 1, Per a 4, Pru ar 1, Pru av 1, Pru p 1, Phl p 1, Phl p2, Phl p 3, Phl p 11, Pla a 2, Poa p 1, Poa p2, Que a 1, Rant t BLG, Ratn 1, Rub I 1, Sal k 1, Sus s 1, Tri a 1, Tri a 2, Tria p 1, Tyr p 13,Ves v 5, Vig r 1, Zea m 1, Zea m3 and lipocalins of insects, ticks,spiders and fungi.

The treatment of the present invention can be performed in the usualmanner of immunotherapies (see e.g.: Cox et al, Task Force ReportJournal of Allergy and Clinical Immunology (2011); 127 (1): 1-55),however, usually the amounts at the lower borders of suchimmunotherapies are sufficient for the treatment according to thepresent invention. Accordingly, lipocalin proteins are preferablyapplied through mucosal surfaces or via the subcutaneous, intramuscular,intranasal, intralymphoidal, etc. route. Systemic (SIT), sublingualimmunotherapy (SLIT) and oral immunotherapy (OIT) also being preferredembodiments of the present invention.

According to a preferred embodiment of the present invention thelipocalin proteins are used for treatment at a concentration above 0.1μg/ml, most preferably 10-100 μg/ml, or up to 600 μg/ml (see e.g.recommendation of WHO; generally higher doses have been regarded asbeing more effective; according to the present invention, overallreduction of doses can be achieved by the provision of lipocalinholo-allergens). Preferred concentrations of the administered lipocalinproteins are therefore 0.1 to 600 μg/ml, preferably 0.5 to 100 μg/ml,especially 1 to 50 μg/ml. Examples of typical dose regimen of standardallergen immunotherapy are disclosed e.g. in Klimek et al., Clin. Exp.Allergy 42 (2012), 936-945): 20, 40, 80 or 120 μg of total grass pollenrecombinant protein. The advantage of the present invention is that dueto higher efficacy of siderophore-loaded lipocalins, the doses can bereduced as well as the number of immunization intervals, lowering therisk of side effects. This is an advantageous therapy option in foodallergy, which is associated with a high risk today and actually istherefore currently not performed in an efficient manner.

According to the present invention, lipocalin proteins are used inholo-form for specific immunotherapy against allergies.

According to another aspect, the present invention also relates tolipocalin proteins for use in treatment or prevention of autoimmunitydiseases, especially celiac disease or inflammatory bowel disease(Crohn's disease, ulcerative colitis). These diseases can be defined asimmunological disorders caused by a loss in immunological toleranceresulting in inflammation. Application of immunesuppressive lipocalinproteins in their holo-form might therefore be an attractive tool forimmunosuppression and induction of tolerance due tobystander-suppression (Mayer L et al; Nature Rev. Immunol 2004)

According to the present invention, lipocalin proteins are co-appliedwith siderophores and ligands such as iron or retinoic acid. Theformulation is preferably achieved by micro- or nanoparticles entrappingthe lipocalin of the invention inside, more preferred, when themicroparticles are constituted by poly lacto glycolic acid (PLGA), morepreferred when the particle is functionalized by lectins to targetimmune induction sites, such as wheat germ agglutinin (WGA), mostpreferred when functionalized with Aleuria aurantia lectin (AAL) whichtargets alpha-L fucose expressed on M-cells of tonsils and Peyers'patches in the intestine. The particulate formula may be applied withadjuvants such as Montanide, Aluminiumhydroxide, diphtheria orcholeratoxin subunits B. The same formula can also be used in asubcutaneous or intramuscular application.

Besides lipocalin proteins, also lipocalin analogues can be used in thetreatment according to the present invention. “Lipocalin analogues”according to the present invention include all polypeptides that exertthe same allergenic specificity as the naturally occurring lipocalinproteins and have a cavity capable of carrying iron or other ligandstypically for lipocalin, such as siderophore-bound iron or retinoicacid. Accordingly, by such definition, lipocalins that do not bind ironefficiently (e.g. via a siderophore) are not to be regarded as“lipocalin analogues” according to the present invention, whereaspolypeptides that bind iron (via siderophores) in an efficient manner(as e.g. confirmed by the method according to the present invention),can also be successfully administrated in the therapeutic embodiment ofthe present invention.

The invention is further disclosed by means of the following examplesand the figures.

FIG. 1: Most prominent respiratory allergens are lipocalins. Structuralcomparison of lipocalins. The crystal structure of human NGAL wild-typeprotein (1L6M) is shown as a ribbon diagram in cyan with superposedblock segments determined with FATCATflex colored in deeper blue. a-c.Single-block superposition with a. bos BLG (3NPO, pink and deep purple),b. dog Can f 1 (model structure, pale green and deep green), and c. CatFel d 4 (model structure, white and deep gray) d. Three-blocks, 2-twistssuperposition with birch Bet v 1 (1BV1, salmon and deeper red hues forthe three segments). e. Two-blocks, 1-twist superposition withAlternaria Alt a 1 (3V0R, light orange and yellow and orange for the twosegments). f. Scores of FATCATflex, CE, and TM superposition methodsused for structural comparisons.

FIG. 2: Allergics have lower LCN2-levels in serum. Serum of healthy andallergic individuals were tested by ELISA for LCN2-levels. In sera ofallergic individuals significantly less lipocalin 2 is detected comparedto controls (A). In allergics, male individuals had significantly morelipocalin 2 than female subjects in serum (B). Compared to non-allergiccontrols, lipocalin2-levels in females (C) and males (D) were lower inallergics. All in vitro assays were performed at least twice with highlyreproducible data sets. Statistical analyses were conducted withStudent's t-test. *p<0.05, **p<0.01, ****p<0.0001.

FIG. 3: Apo-, but not holo-Lipocalin allergens promote CD4 cellsurvival. 10000 CD3+ cells of PMA-activated PBMCs incubated with apo- orholo-lipocalin allergens were recorded and analyzed for CD4 and CD8expression. Representative pictograms of CD3 gated PBMCs stained for CD4and CD8 as well as summary of CD4 expression (standardized byPMA-control) of individuals tested are depicted, when incubated with a.BLG b. Bet v 1 c. Alt a 1 in the apo and holoform. Statistical analyseswere conducted with paired Student's t-test. **p<0.01, ****p<0.0001.Data a are from 9 independent experiments with n=26, b from 5experiments with n=10 and c from 4 experiments with n=7.

FIG. 4: Th2-cytokines are released upon stimulation with lipocalinallergens in their apo- but not in their holo-form. PMA-activated PBMCswere incubated for 18-24 h with a. apo- and holo-BLG b. apo- andholo-Bet v 1 c. apo- and holo-Alt a 1 and their cytokine-contentanalyzed for IL13 and IFN-γ. *p<0.05, **p<0.01, were obtained usingpaired Student's t-test. Data a are from 9 independent experiments withn=26, b from 5 experiments with n=10 and c from 4 experiments with n=8.

FIG. 5: Iron-binding of BLG. Autofluorescence of the cavity was quenchedby addition of siderophore (y-axis) and increasing concentrations ofiron (x-axis).

FIG. 6A and FIG. 6B: Serum LCN2 increases after sublingual immunotherapy(SLIT) against grass in allergics. Allergics were randomized andreceived either placebo (n=10; FIG. 6B) or sublingual immunotherapy(n=33; FIG. 6A) against grass pollen for 26 weeks. Before (Preslit),within (midslit) and after final SLIT-treatment (post-SLIT) bloodsamples were taken. Three to six months after termination ofSLIT-treatment blood was collected in up to two follow-up visits (post Iand post II) and analyzed for serum-LCN2 by ELISA.

EXAMPLES

1. Allergics have Lower LCN2-Levels in Serum than Healthy Controls.

The study according to the present invention was approved by theinstitutional ethics committee and conducted in accordance with theHelsinki Declaration of 1975. The present study was divided into twoparts: for detection of LCN2 in serum a retrospective analysis ofprospectively collected samples was conducted, and the second part forisolation of white blood cells. In part one, LCN2 in serum was detectedby retrospective analysis. In part two white blood cells were isolated.A total of 143 subjects with suspicion of allergy were tested in anallergy ambulatory for allergen-specific IgE using a microarray-basedpanel of 112 allergens (ISAC®, Phadia, Sweden) (FIG. 2). Sample size wascalculated post hoc (a err 0.05, effect size 0.8) with the poweranalysis program G*Power 3.1.7 and reached a power of >0.95.Subsequently, LCN2-levels in serum were tested. ELISA plates were coatedwith rat anti-human Lipocalin 2 (R&D, 2 μg/ml), blocked with 1% BSA/PBSand diluted serum (1:100) or standards were incubated for 3 hours beforedetecting with biotinylated goat anti-human Lipocalin 2 (100 ng/ml) andStreptavidin-peroxidase (1:200). As substrate TMB was used and stoppedafter 10 min with 1.8 M sulfuric acid. Absorbance was measured at 450nm, with a reference wavelength of 630 nm.

Patients were considered lipocalin-allergic (A&IgE) when they sufferedfrom a history of rhinoconjunctivities associated withlipocalin-allergens and had IgE against at least one of followinglipocalin-allergens on the microarray: Alt a 1, Bet v 1, Bos d 5, Can f1 and Can f 2, Der p 2, Der f 2, Equ c1, Fel d 4, Mal d1, Phl p 1 andPhl p 2. Patients with a history of asthma or atopic dermatitis wereexcluded due to previously reported intrinsic upregulation of LCN2(n=25). According to published data on age-dependent gender bias inallergic and atopic diseases in humans, we excluded patients under theage of 18 (n=9) and divided the data by gender. All others wereconsidered controls due to unspecific symptoms and history, and negativeIgE to lipocalin allergens.

2. Nearly all Major Respiratory and Some Food Allergens Belong to theLipocalin-Family. Structural Analysis

Three different superposition procedures were employed to comparestructure of allergens using (i) FATCAT (Flexible structure AlignmenT byChaining Aligned Fragment Pairs), which allows flexibility instructurally aligned blocks by introducing a limited number of twists inthe superposed structures (Ye et al., Bioinformatics 19 (2003), Suppl 2,ii246), (ii) CE (Combinatorial Extension) algorithm to alignstructurally fragment pairs (Shindyalov et al., Protein engineering 11(1998), 739), and (iii) TM (Template Modeling)—align procedure whichuses rotation matrices and Dynamic Programming to optimize a structurealignment (Zhang et al., Nucleic acids research 33 (2005), 2302). BothCE and TM methods yield superpositions referring to the proteinstructure as a whole, whereas FATCATflex superpositions may give two ormore superposed structural blocks if one or more twists are introduced(as it is the case here for Bet v 1 and Alt a 1 proteins: see FIG. 1).

For comparisons between crystal structures, FATCATflex and CEsuperpositions were accomplished by using the j-interface versions ofthese methods implemented in the PDB Comparison Tool (Prlic et al.,Bioinformatics 26 (2010), 2983). For FATCATflex comparisons involvingmodel structures, the FATCAT server and a version compiled for Linux ofthe CE program were used instead (Ye et al., Nucleic acids research 32(2004), W582). TM-align superpositions were carried out in all casesusing the TM website which allows comparing experimental as well astheoretical structures. Superposed structures with FATCATflexp-values<0.05 are considered significantly similar, CE superpositionswith z-scores between 3.0 and 4.0 suggest structural similarity, andTM-align superpositions with TM-scores between 0.4 and 0.5 indicatesignificant structural relationship.

Structures for Can f 1 and Fel d 4 allergens were obtained by homologymodeling with SwissModel (Kiefer et al., Nucleic acids research 37(2009), D387) in automated mode. Can f 1 structure (QMEANZ-score=+0.503, Evalue=2.34×10⁻⁴¹) was modeled based on template 3EYC(60.14% sequence identity) whereas Fel d 4 model structure (QMEANZ-score=−0.875, Evalue=5.10×10⁻⁵²) was obtained based on template 1EW3(69.68% sequence identity).

Structural comparisons between NGAL wild-type protein and the allergensBLG, Can f 1, Fel d 4, Bet v 1 and Alt a 1 were studied using the X-raycrystal structures (PDB code in parentheses) for NGAL (1L6M), bos BLG(3NPO), birch Bet v 1 (1BV1), and Alternaria Alt a (3V0R), and themodeled structures for dog Can f 1 and cat Fel d 4.

The results are given in FIG. 1 and show that the selected allergens,against the state of the art, form similar folds in the analysisprompting the conclusion that the lipocalin fold is a significantprecondition for allergenicity.

3. Lipocalin Proteins without Binding to Siderophores Cause a Th2-Shift.

In the following experiments it was shown that by pre-activatingperipheral blood mononuclear cells, PBMCs, for 24 h with suboptimalconcentration of phorbol-12-myristate-13 acetate, PMA (0.75 ng/ml), andaddition of apoBLG or apoBetv1 (100 μg/ml), an increase in CD4expression and survival is observed, which was in sharp contrast whensame cells were incubated with the holo counterpart containing iron,e.g. holoBLG or holoBetv1 (Liu et al., The Journal of BiologicalChemistry 2011; 286: 20606-20614). Cells were then stained for CD3-APC,CD8-PE, CD4-PE-CY7, 7AAD and Annexin V-FITC, gated for CD3 and analyzedby a FACS Canto II. Data acquisition was stopped when 10000 CD3 cellswere recorded.

The data showed that apo-lipocalins promote survival of activatedCD4-cells, whereas holo-lipocalins reduce CD4+ expression on CD3+ cellsand promote cell death of CD3+CD4+ cells. Thus, addition ofiron-siderophore to an immunotherapeutic agent significantly modulates aconsecutive immune response. This for the first time allows usinglipocalin allergens for immunotherapy without causing an undesiredTh2-shift.

The advantage of the present invention for immunotherapy is that the useof lipocalins in combination with siderophore-iron-complex inimmunotherapy does not cause a Th2-shift and even counterregulate theTh2 bias typical for allergy, thereby abrogating an immune response andthereby leading to a modulation of the immune response to allergens.Moreover, allergen extracts and molecules can be designed according totheir apo- or holo-state to redirect the immune response.

4. Lipocalin Proteins for Use in the Treatment of Allergy and Monitoringof Lipocalin 2 (LCN2) Levels to Assess Allergen Immunotherapy Efficacy.

LCN2-levels in serum of an allergic individual were measured before andafter 4 months sublingual immunotherapy against horse dander allergy byELISA. LCN2-levels in serum increased during this time course from 780ng/ml to 950 ng/ml.

Materials & Methods

General: Commercially available bovine beta-lactoglobulin (SigmaAldrich, Steinheim, Germany) and recombinant Alternaria alternata (BialAristegui, Bilbao, Spain) were prior to use dialyzed first against 10 μMDFO before further dialyzation against deionized water. Recombinant Betv 1a (Biomay, Vienna, Austria) was used as purchased. The molecularmodelling approach and used software is in detail described in theresults' section of FIG. 1.

Generation of Holo-Allergens (Examples 3+4)

Apo-allergens were incubated with equimolar concentration of iron(ammonium iron (III) citrate, Sigma) and three-fold molar concentrationof catechol, since 3 catechols are necessary for hexadental binding ofiron in the LCN2-pocket against deionized water. Recombinant Bet v1a(Biomay, Vienna, Austria) was used as purchased

Isolation of PBMCs (Examples 3+4)

An additional ethical consideration was required for the analysis ofblood samples, which was approved by the institutional ethics committeeand conducted in accordance with the Helsinki Declaration of 1975. Thestudy was conducted on 30 volunteer blood donors. All subjects gavetheir full written informed consent, and the study was approved by theMedical University of Vienna ethics committee. Volunteers were dividedinto two groups (allergics and with no reported allergies) and 15 mlblood were taken.

Blood was mixed with equal volumes of PBS containing 2% FCS beforeapplying onto 10 ml Ficoll-Paque PLUS (GE Healthcare, Uppsala, Sweden),centrifugation at 400 g for 30 min without brake and washing the cellstwice with 0.89% sodium chloride solution. Cells were then diluted to aconcentration of 1Mio cells/ml in RPMI medium containing 10% FCS.Throughout the study FCS from the same lot was always used.

Stimulation of PBMCs with allergen (Examples 3+4)

To PBMCs (0.5 Mio/test) a final concentration of 0.75 ng/ml PMA, 100μg/ml apo-allergen (BLG, Alt a 1 and Bet v 1) with or without 10 μMcatechol (Sigma) and 10 μM iron was added. For control purposes eachsubstance was also tested without allergen or PMA. PMA concentration wasdetermined in pre-experiments and considered optimal when cells wereslightly downregulating surface CD4+ expression (7). After 18-24 hsupernatants were collected and stored at −80° C. until furtheranalysis.

Cells were stained for 30 min at 4° C. with CD3-APC (clone SK7,ebioscience), CD4-PE-Cy7 (clone SK3, BD Bioscience), CD8-PE (clone SK1,BD Bioscience), in PBS containing 2% FCS, followed by 10 min incubationof Annexin V FITC (BD Bioscience) and 7AAD (ebioscience) in Bindingbuffer (10 mM Hepes, 140 mM NaCl, 2.5 mM CaCl₂)) at room temperature.Acquisition and analysis was performed on a FACS Canto II machine (BDBioscience, San Jose, Calif., USA) using the FACSDiva Software 6.0.

Determination of LCN2 and Cytokines (Examples 2+4)

LCN2 and the cytokine levels of IL13 and IFNγ were detected withcommercially available kits according to the manufacturers' protocol.Sera were diluted 1:100 before determining LCN2-levels, whereassupernatants of 18-24 h stimulation were used undiluted. Sensitivity ofLCN2 assay is about 75 μg/ml and kits were purchased from R&D Systems(Minneapolis, Minn., USA), whereas ELISAs for human IL13 and IFNγ werefrom ebioscience (Santa Clara, Calif., USA), both assays having areported sensitivity of 4 μg/ml.

5. Testing of Iron-Binding Capacity of Lipocalin Allergens

In this assay, 2 μM of allergen (in the example BLG) and 50 μM ofsiderophores like 2,3, Dihydroxybenzoic Acid are incubated withincreasing concentrations of iron III (Fe3+) ranging from 0 to 50 μM(x-axis in FIG. 5). Quenching of autofluorescence is measured atexcitation and emission wavelengths of 280 and 340 nM respectively inendpoint mode (y-axis in FIG. 5).

6. Serum LCN2 Increases after Sublingual Immunotherapy (SLIT)

LCN2 was detected with commercially available kits according to themanufacturers' protocol. Sera were diluted 1:200 before determiningLCN2-levels. LCN2 kits were purchased from R&D Systems (Minneapolis,Minn.). Allergics were randomized and received either placebo (n=10) orsublingual immunotherapy (n=33) against grass pollen for 26 weeks.Before (Preslit), within (midslit) and after final SLIT-treatment(post-SLIT) blood samples were taken. Three to six months aftertermination of SLIT-treatment blood was collected in up to two follow-upvisits (post I and post II) and analyzed for serum-LCN2 by ELISA.

This experiment revealed that serum LCN2 increases after SLIT againstgrass in allergics (see FIG. 6A and FIG. 6B).

The present invention discloses the following embodiments:

1. A method for diagnosing allergy in a human or animal patient, whereinthe level of species-specific lipocalin, especially lipocalin 2 in ahuman patient, is measured in a sample of said patient and wherein alowered level of said lipocalin compared to the level of said lipocalinin the corresponding sample of a human or animal that has no allergy, isindicative of an allergy.2. Method according to embodiment 1, wherein the sample is a body fluid,preferably a blood, serum, plasma, urine, saliva, tear fluid, lymph, ormucosa sample, a dander sample, or a hair sample.3. Method according to embodiment 2, wherein the body fluid is blood,serum or plasma and the patient is a human patient or veterinarianpatient, preferably dog, cat, or horse.4. Method according to any one of embodiments 1 to 3, wherein the levelof species-specific lipocalin, especially lipocalin 2, is lowered by atleast 5% with respect to the ng lipocalin 2/ml body fluid, preferably byat least 10%, especially at least 15%, compared to the level ofspecies-specific lipocalin, especially lipocalin 2, in the correspondingsample of a human or animal that has no allergy, said correspondingsample having no allergy defining the 100% level.5. Method according to any one of embodiments 1 to 4, wherein the levelof species-specific lipocalin, especially lipocalin 2, is measured byimmunological techniques, especially by ELISA, ELISPOT, immunoblot, orother immunological solid phase assays; or by measuring the level ofspecies-specific lipocalin mRNA, especially lipocalin 2 mRNA, in thesample, preferably by PCR, especially real time PCR.6. Kit for performing a method according to any one of embodiments 1 to5, comprising

-   -   means for detecting the level of a species-specific lipocalin,        especially lipocalin 2, especially a molecule binding to the        species-specific lipocalin, especially lipocalin 2, and    -   means for comparing the level of the species-specific lipocalin,        especially lipocalin 2, to be detected with the level of the        species-specific lipocalin, especially lipocalin 2, in a human        or animal that has no allergy.        7. Kit according to embodiment 6, wherein the means for        detecting the level of species-specific lipocalin, especially        lipocalin 2, is an anti-species-specific lipocalin antibody,        preferably an anti-lipocalin 2 antibody or a lipocalin 2-binding        antibody fragment, especially an anti-human lipocalin 2 antibody        or a human lipocalin 2-binding antibody fragment.        8. Kit according to embodiment 6 or 7, further comprising a        marker, preferably a colourigenic, fluorescent, luminescent,        magnetic or radioactive marker, especially a marker that is        covalently linked to the means for detecting the level of a        species-specific lipocalin, especially lipocalin 2, or a marker        that is covalently linked to the molecule binding to a        species-specific lipocalin, especially lipocalin 2.        9. Kit according to any one of embodiments 6 to 8, further        comprising one or more standards for a species-specific        lipocalin, especially lipocalin 2.        10. Method for determining the quantity of unloaded lipocalin 2        in a lipocalin 2 containing preparation wherein        (a) either a predetermined amount of test siderophore is added        to the preparation or        (b) the preparation is competitively tested with iron-ligands        not able to bind to the lipocalin cavity, preferably desferral,        that extracts ligands from the lipocalin-pocket resulting in the        reestablishment of the intrinsic fluorescence of the proteins;        or        (c) fluorescent, chromogenic, radiolabelled        siderophore-iron-complexes are used directly or competitively        for binding to the lipocalin cavity and wherein the quantity of        unloaded lipocalin 2 is determined by        (a) quenching of the autofluorescence of lipocalin proteins        (b) autofluorescence of lipocalin proteins, or        (c) measurement of bound siderophore.        11. Lipocalin proteins for use in treatment or prevention of        allergies, wherein the lipocalin proteins are provided together        with a siderophore and a metal ion, especially an iron ion, in        their holo-form.        12. Lipocalin proteins according to embodiment 11, wherein the        treatment is a reduction and amelioration of allergy symptoms        13. Lipocalin proteins according to embodiments 11 or 12,        wherein the lipocalin proteins are administered in combination        with metal-ions, preferably Fe, Cu, Zn, Se or Mn, especially        iron Fe³⁺.        14. Lipocalin proteins according to any one of embodiments 11 to        13, wherein lipocalin proteins are administered together with a        metal-ion, preferably iron complexed with siderophores, in a        molar ratio of 0.5 to 3 to 3 to 0.5, preferably in a molar ratio        of 1 to 3 to 3 to 1, especially in a molar ratio of 2.0 to 3 to        3 to 2.        15. Lipocalin proteins according to any one of embodiments 11 to        14, wherein lipocalin proteins are administered with zinc-,        copper-, selen-, or mangan-ions.        16. Lipocalin proteins according to any one of embodiments 11 to        15, wherein lipocalin proteins are administered with        siderophores selected from catechols or catechol-derivatives        comprising 2 hydroxygroups in ortho position.        17. Lipocalin proteins according to any one of embodiments 11 to        15, wherein lipocalin proteins are administered with        siderophores selected from the hydroxamate and hydroxypyridinone        ligand families as well as of carboxylate and its derivates        where in the α-position a hydroxy- or amino-group is present.        17. Lipocalin proteins according to any one of embodiments 11 to        16, wherein lipocalin proteins are selected from human lipocalin        2, Amb a 1, Aln g 1, Aca s 13, Act c 8, Act d 8, Act d 11, Alt a        1, Asp f 1, Asp f 3, Asp f 6, Art v 1, Api g 1, Api ml, Act d 2,        Act d 8, Ara h 8, Arg r 1, Ber e 1, Bet v 1, Bet ch 1, Bet co 1,        Bet le 1, Bet n 1, Bet p 1, Blo t5, Bla g 1, Bla g 4, Bos d 2,        Bos d 5, Bub b BLG, Can f 1, Canf 2, Can f 6, Cap h BLG, Car b        1, Cas s 1, Cav p 1, Cav p 2, Cav p 3, Cla h 8, Cyn d 1, Cyn d        2, Cyn d 15, Cor a 1, Cor he 1, Che a 1, Cup a 1, Dac g 1, Dac g        2, Dac g 3, Dau c 1, Der p 2, Der f 2, Der f 13, Der p 13, Ecqu        c 1, Ecqu c 2, Fag s 1, Fra a 1, Fel d 4, Fel d 7, Gly m 4, Hol        l 1, Hom s TL, Hey b 8, Jug r 2, Lep d 13, Lol p 1, Lol p 2, Lol        p3, Lyc e 4, Mal d 1, Mer a 1, Mus m 1, Ole e 1, Ory c 1, Ory s        1, Ost c 1, Ovi a BLG, Pas n 1, Pha a 1, Per a 4, Pru ar 1, Pru        av 1, Pru p 1, Phl p 1, Phl p 2, Phl p 3, Phl p 11, Pla a 2, Poa        p 1, Poa p2, Que a 1, Rant t BLG, Rat n 1, Rub I 1, Sal k 1, Sus        s 1, Tri a 1, Tri a 2, Tria p 1, Tyr p 13, Ves v 5, Vig r 1, Zea        m 1, Zea m3 and lipocalins of insects, ticks, spiders and fungi.        18. Lipocalin proteins according to any one of embodiments 11 to        17, wherein lipocalin proteins are applied in a systemic        immunotherapy, sublingual immunotherapy or oral immunotherapy.        19. Lipocalin proteins according to any one of embodiments 11 to        18, wherein lipocalin proteins are applied intramuscularly,        intranasally, or intralymphatically.        20. Lipocalin proteins according to any one of embodiments 11 to        19, wherein lipocalin proteins are applied through mucosal        surfaces or via the subcutaneous route.        21. Lipocalin proteins according to any one of embodiments 11 to        20, wherein lipocalin proteins are used at a concentration of        0.1 to 600 μg/ml, preferably of 0.5 to 100 μg/ml, especially 1        to 50 10 μg/ml.

1. A method for treating or preventing allergies, which comprises administering to a patient in need thereof, a therapeutically effective amount of lipocalin proteins, wherein the lipocalin proteins are provided together with a siderophore and a metal ion in their holo-form.
 2. The method according to claim 1, which comprises a reduction and amelioration of allergy symptoms.
 3. The method according to claim 1, wherein the lipocalin proteins are administered in combination with one or more metal-ions selected from Fe, Cu, Zn, Se and Mn.
 4. The method according to claim 1, wherein lipocalin proteins are administered together with a metal-ion in a molar ratio of 0.5 to 3 to 3 to 0.5.
 5. The method according to claim 1, wherein the lipocalin proteins comprise one or more lipocalins selected from human lipocalin 2, Amb a 1, Aln g 1, Aca s 13, Act c 8, Act d 8, Act d 11, Alt a 1, Asp f 1, Asp f 3, Asp f 6, Art v 1, Api g 1, Api ml, Act d 2, Act d 8, Ara h 8, Arg r 1, Ber e 1, Bet v 1, Bet ch 1, Bet co 1, Bet le 1, Bet n 1, Bet p 1, Blo t5, Bla g 1, Bla g 4, Bos d 2, Bos d 5, Bub b BLG, Can f 1, Canf 2, Can f 6, Cap h BLG, Car b 1, Cas s 1, Cav p 1, Cav p 2, Cav p 3, Cla h 8, Cyn d 1, Cyn d 2, Cyn d 15, Cor a 1, Cor he 1, Che a 1, Cup a 1, Dac g 1, Dac g 2, Dac g 3, Dau c 1, Der p 2, Der f 2, Der f 13, Der p 13, Ecqu c 1, Ecqu c 2, Fag s 1, Fra a 1, Fel d 4, Fel d 7, Gly m 4, Hol l 1, Hom s TL, Hey b 8, Jug r 2, Lep d 13, Lol p 1, Lol p 2, Lol p3, Lyc e 4, Mal d 1, Mer a 1, Mus m 1, Ole e 1, Ory c 1, Ory s 1, Ost c 1, Ovi a BLG, Pas n 1, Pha a 1, Per a 4, Pru ar 1, Pru av 1, Pru p 1, Phl p 1, Phl p 2, Phl p 3, Phl p 11, Pla a 2, Poa p 1, Poa p2, Que a 1, Rant t BLG, Rat n 1, Rub I 1, Sal k 1, Sus s 1, Tri a 1, Tri a 2, Tria p 1, Tyr p 13, Ves v 5, Vig r 1, Zea m 1, Zea m3 and lipocalins of insects, ticks, spiders and fungi.
 6. The method according to claim 1, wherein the lipocalin proteins are administered using systemic immunotherapy, sublingual immunotherapy or oral immunotherapy.
 7. The method according to claim 1, wherein the lipocalin proteins are administered intramuscularly, intranasally, intralymphatically or through mucosal surfaces or via the subcutaneous route.
 8. The method according to claim 1, wherein the lipocalin proteins are administered at a concentration of 0.1 to 600 μg/ml. 